Date: Mon, 5 Feb 2001 20:02:30 -0700 From: "Kenneth D. Merry" <ken@kdm.org> To: Tom Samplonius <tom@sdf.com> Cc: Mike Smith <msmith@FreeBSD.ORG>, freebsd-scsi@FreeBSD.ORG Subject: Re: Tags and the mly driver Message-ID: <20010205200229.A88285@panzer.kdm.org> In-Reply-To: <Pine.BSF.4.05.10102051754190.21039-100000@misery.sdf.com>; from tom@sdf.com on Mon, Feb 05, 2001 at 06:02:04PM -0800 References: <20010205152804.A85729@panzer.kdm.org> <Pine.BSF.4.05.10102051754190.21039-100000@misery.sdf.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Feb 05, 2001 at 18:02:04 -0800, Tom Samplonius wrote: > On Mon, 5 Feb 2001, Kenneth D. Merry wrote: > > ... > > I don't know what that message is about, but from what I can see, we should > > only be sending one command to that device at a time, and there shouldn't > > be any way we could send any more, since the device doesn't claim to > > support tagged queueing. > > > > So, in short, it doesn't look like your problem is related to trying to > > increase the tags, since I don't think you can. > > Well, that it isn't too good. That would mean CAM is serializing all IO > to the mly driver, right? That would be a likely reason why the mlx > based cards are faster than the mly based cards, as the mlx driver does > not go through the CAM layer. In practice, cards using the mly based > cards are quite a bit slower than mlx cards, even though mly based cards > all have faster processors, more cache, faster SCSI channels, and 64bit > PCI. Right, all I/O to the board is being serialized. That could explain why things are slower. > > To verify this, try: > > > > camcontrol tags da0 -N 4 -v > ... > > > > Then you can't do tagged queueing and the settings aren't having any > > effect. If dev_openings + dev_active are greater than 1, we've got a > > problem, since we shouldn't be allowing that to happen for a device that > > doesn't claim to support tagged queueing. > > "camcontrol tags da0 -N 4" increases the number openings. I can even > see that actually working a bit, as dev_active is > 1 when repeatedly > checking with camcontrol. However, shortly there after, the mly driver > hangs. That shouldn't be possible. What version of FreeBSD are you using? > ... > > Yeah, camcontrol bails if the get transfer settings CCB fails, although > > you'll still see 'Tagged Queueing Enabled' in the dmesg if the array > > actually supports it. > > It really isn't what the array supports, but the driver, isn't it? The > dpt driver presents a single virtualized SCSI disk to the CAM layer. Well, it's a combination of what the card firmware supports and what the driver supports. Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20010205200229.A88285>